Memory devices are typically provided as internal, semiconductor, integrated circuit devices in computers or other electronic devices. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), and flash memory.
Flash memory devices have developed into a popular source of non-volatile memory for a wide range of electronic applications. Flash memory devices typically use a one-transistor memory cell that allows for high memory densities, high reliability, and low power consumption. Changes in threshold voltage (Vt) of the memory cells, through programming (which is often referred to as writing) of charge storage structures (e.g., floating gates or charge traps) or other physical phenomena (e.g., phase change or polarization), determine the data state (e.g., data value) of each memory cell. Common uses for flash memory include personal computers, personal digital assistants (PDAs), digital cameras, digital media players, cellular telephones, solid state drives and removable memory modules, and the uses are growing.
Programming in memories is typically accomplished by applying a plurality of programming pulses, separated by verify pulses, to program each memory cell of a selected group of memory cells to a respective intended data state (which may be an interim or final data state). With such a scheme, the programming pulses are applied to access lines, such as those typically referred to as word lines, for selected memory cells. After each programming pulse, one or more verify pulses are used to verify the programming of the selected memory cells. Current programming typically uses many programming pulses in an incremental step pulse programming scheme, where each programming pulse is a single pulse that moves the memory cell threshold voltage by some amount. Before each programming pulse, word lines may be precharged, and after each programming pulse, the word lines may be discharged. This can lead to high power consumption.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternative methods of operating memory, and apparatus to perform such methods.